Field of the Invention
The invention relates generally to storage vessels and, more particularly, containers and lids.
Related Art
In modern commerce and applications, containers are used in a vast array of applications, some more demanding than others.
To be economically and environmentally efficient, containers (like other manufactured items) need to use a minimum amount of material. Not only does this reduce the waste that results at the end of the container's useful life, it also reduces the costs of materials to manufacture the container, reduces the transportation costs that can be involved in using the container, and provides other benefits. For containers made from plastic or similar materials, the costs of materials and the costs of achieving ecological responsibility can be substantial.
On the other hand, many or even most containers require some degree of reliable structural integrity. Among other things, they may be stacked three or four (or more) high on pallets for storage and/or transportation, and there may be other pallets or objects stacked on top of those stacks.
Square, rectangular or other cornered containers can more efficiently use a given volume of space on a pallet and/or in a warehouse or retail store (as compared to conventional round plastic buckets). They can benefit from the foregoing reduction in material usage and can provide design and performance challenges as compared to non-cornered containers.
Design and performance characteristics for a container or other product also may be important with respect to material selection. For example, in certain applications, one material may be preferred or even required instead of another (e.g., polypropylene instead of polyethylene) in order to meet performance criteria (such as the ability to withstand anticipated vertical compression loads or other forces).
In addition, reducing the nonmaterial costs of manufacture also improves the economic and ecological considerations of making and using a given container. For example, to the extent that the energy requirements for making a given container can be reduced, the economic and environmental characteristics of the container and fabrication process are also improved. For applications and processes such as injection molding of plastic containers or other products, a lower injection pressure (to inject the plastic into a mold) can mean that less energy is needed to manufacture that product.
Accordingly, it is desirable to provide methods and apparatus for containers having sufficient strength and durability to withstand heavy loads and predictable storage and handling risks, while reducing costs and usage of materials and providing other benefits.
Containers (such as plastic injection-molded buckets or pails or the like) come in a wide variety of shapes and sizes. Commonly, these have generally flat and/or smooth curved sidewalls. Sometimes reinforcing ribs or other features are formed or provided on the exterior and/or interior of the container. In many applications, the containers are designed to be nestable and stackable. When the containers are filled, the stacking loads can be substantial, and the sidewalls typically have to be designed and tested to support and withstand certain threshold requirements (to avoid failure when they are dropped or stacked, etc.).
When sufficient force is exerted downwardly on such containers, the container can collapse or “fail.” Commonly, this failure begins with or includes the weakest point of the container sidewall buckling in or out (toward or away from the inside of the container). Among other situations, such loading and buckling failures can occur when filled containers are stacked too high on top of each other. Even for unstacked single containers, however, sufficient force can cause such a failure.
Thus, there is a need to provide a container with improved strength and durability that can withstand heavy loads (such as weight imposed by stacking filled containers, or any other kind of force applied downwardly) without bending or crumpling.
In addition, containers may need to include provisions for being child resistant, for example, to prevent access to hazardous materials. Improved features may also be necessary in order to prevent unintentional access to container contents, such as in storing or transporting hazardous materials.
Tear strips have commonly been provided to enable relatively easy removal of lids from their associated containers. They can also provide some evidence of tampering with respect to the sealed container (e.g., whether the sealed container has been opened previously). Such tear strips have been provided within injection-molded lids, among others.
Within injection-molded lids, however, it can remain relatively difficult for a user to grasp the end of the tear strip to initiate removal of the tear strip. Simple tabs formed at the end of the tear strip remain relatively unsatisfactory in that regard, at least in comparison to the present invention. Other approaches do not provide a reusable lid to cover the container opening once the tear strip is removed, require more complicated molding, may be less capable of being stacked and nested (especially with other existing containers and lids), and have other shortcomings.
Accordingly, it is an object of this invention to provide an improved solution incorporating a tear strip combination.